This invention pertains to fused material comprised of aluminum oxycarbide/nitride-Al2O3.rare earth oxide eutectics. Examples of useful articles comprising fused aluminum oxycarbide/nitride-Al2O3.rare earth oxide eutectic material include fibers and abrasive particles.
A variety of fused eutectic metal oxide materials are known in the art, including binary and ternary eutectic materials. Fused eutectic metal oxide materials are typically made by charging a furnace with sources of the various metal oxides, as well as other desired additives, heating the material above its melting point, and cooling the melt to provide a solidified mass (see, e.g., U.S. Pat. No. 1,161,620 (Coulter), U.S. Pat. No. 1,192,709 (Tone), U.S. Pat. No. 1,247,337 (Saunders et al.), U.S. Pat. No. 1,268,533 (Allen), and U.S. Pat. 2,424,645 (Baumann et al.) U.S. Pat. No. 3,891,408 (Rowse et al.), U.S. Pat. No. 3,781,172 (Pett et al.), U.S. Pat. No. 3,893,826 (Quinan et al.), U.S. Pat. No. 4,126,429 (Watson), U.S. Pat. No. 4,457,767 (Poon et al.), U.S. Pat. No. 5,143,522 (Gibson et al), U.S. Pat. No. 5,023,212 (Dubots et. al), and U.S. Pat. No. 5,336,280 (Dubots et. al)).
There is, however, a continuing desire for new materials which may offer performance characteristics (including combinations of characterstics) that are different than conventional materials, are easier to make, and/or cheaper to make.
The present invention provides a fused, crystalline eutectic material comprising eutectic of at least (i) crystalline, complex Al2O3.REO, and (ii) at least one of aluminoxy-D or M-aluminoxy-D, wherein D is at least one of carbide or nitride, and M is at least one metal cation other than Al (e.g., at least one of Ti, Mg, Sr, Ca, Ba, Zr, or Sc). Preferably, a fused, crystalline material according to the present invention comprises, on a theoretical oxide basis, at least 30 percent (or even at least 40, 50, 60, 70, 80, or 90 percent) by weight Al2O3, based on the total metal oxide, metal carbide, and metal nitride content of the material.
Preferred eutectics may include Al3O3Nxe2x80x94Yb3Al5O12, Al3O3Nxe2x80x94Dy3Al5O12, Al3O3Nxe2x80x94GdAlO3, Al2OCxe2x80x94Yb3Al5O12, Al2OCxe2x80x94Dy3Al5O12 and Al2OCxe2x80x94GdAlO3 eutectics.
In this application:
xe2x80x9csimple metal oxidexe2x80x9d refers to a metal oxide comprised of a one or more of the same metal element and oxygen (e.g., Al2O3, CeO2, MgO, SiO2, and Y2O3);
xe2x80x9ccomplex metal oxidexe2x80x9d refers to a metal oxide comprised of two or more different metal elements and oxygen (e.g., CeAl11O18, Dy3Al5O12, MgAl2O4, and Y3Al5O12);
xe2x80x9ccomplex Al2O3.metal oxidexe2x80x9d refers to a complex metal oxide comprised of, on a theoretical oxide basis, Al2O3 and one or more metal elements other than Al (e.g., CeAl11O18, Dy3Al5O12, MgAl2O4, and Y3Al5O12);
xe2x80x9ccomplex Al2O3.Y2O3xe2x80x9d refers to a complex metal oxide comprised of, on a theoretical oxide basis, Al2O3 and Y2O3 (e.g., Y3Al5O2);
xe2x80x9ccomplex Al2O3.rare earth oxidexe2x80x9d refers to a complex metal oxide comprised of, on a theoretical oxide basis, Al2O3 and rare earth oxide (e.g., CeAl11O18 and Dy3Al5O12); xe2x80x9crare earth oxidesxe2x80x9d refer to, on a theoretical oxide basis, CeO2, Dy2O3, Er2O3, Eu2O3, Gd2O3, Ho2O3, La2O3, Lu2O3, Nd2O3, Pr6O11, Sm2O3, Th4O7, Tm2O3, and Yb2O3; and
xe2x80x9cREOxe2x80x9d means rare earth oxide.
In another aspect, the present invention provides a method for making fused, crystalline material according to the present invention, the method comprising:
melting at least one Al2O3 source and at least one rare earth oxide source to provide a melt, wherein and at least one source of nitrogen (e.g. AlN) or carbon (e.g. Al4C3) is provided in the melt; and
converting the melt to the fused, crystalline material.
Fused crystalline material according to the present invention can be made, formed as, or converted into fibers or abrasive particles.